White Rodgers 903990 User manual
Installation
Instructions
for
Heating
only
903990,
903994
&
918082
and
Heating
&
Cooling
903992
&
918081
CONTENTS
Preparations.1
Thermostat
Features.2
Removing
Old
Thermostat.3
Mounting
and
Wiring.4
Set
Heat
Anticipator.5
New
Thermostat
Operation.6
Specifications.7
Troubleshooting.8
YOUR
THERMOSTAT
REPLACES
Description
903990
903994
918082
Standard
Heating
&
Cooling
Systems
-
4
or
5
wires
No
Yes
Standard
Heat
Only
Systems
Yes
Yes
Millivolt
Heat
Only
Systems
-
Floor
or
Wall
Furnaces
Yes
Yes
Standard
Central
Air
Conditioning
No
Gas
or
Oil
Heat
Yes
Yes
Electric
Furnace
Yes
Yes
Hydronic
(Hot
Water)
Zone
Heat
-
2
Wires
Yes
Yes
Hydronic
(Hot
Water)
Zone
Heat
-
3
Wires
No
No
Heat
Pump
(No
Aux
or
Emergency
Heat)
No
Yes
Heat
Pump
(with
Aux
or
Emergency
Heat)
No
No
Baseboard
Electric
Heating
or
Line
Voltage
(120
or
240
Volt)
No
No
Q
PREPARATIONS
Assemble
tools
required
as
shown
below.
HAND
OR
POWER
DRILL
WITH
3M6
INCH
DRILL
BIT.
IF
NEEDED
RAT
SLA06
SCREWDRIVER
WIRE
CUTTER/STRIPPER
[a]
o)c=3(p
SQ[g]
SPIRIT
LEVEL
OR
PLUMB
BOB
AND
UNE
OPTIONAL-
THERMOSTAT
MUST
BE
LEVEL
TO
WORK
PROPERLY
Failure
to
follow
and
read
all
instructions
carefully
be¬
fore
installing
or
operating
this
control
could
cause
personal
injury
and/or
property
damage
Q
THERMOSTAT
FEATURES
MOUNTING
SCREWS
CAPTIVE
SCREWS
Figure
1.
Adaptor
Plate
(optional)
WHITE-RODGERS
EMERSON
ELECTRIC
CO.
9797
REAVIS
ROAD
ST.
LOUIS,
MISSOURI
63123-5398
www.white-rodgers.com
©
REMOVING
OLD
THERMOSTAT
A
CAUTION
To
prevent
electrical
shock
and/or
equipment
damage,
disconnect
electrical
power
to
the
system
at
the
main
fuse
or
circuit
breaker
until
installation
is
complete.
Before
removing
wires
from
old
thermostat's
switching
subbase,
label
each
wire
with
the
terminal
designation
it
was
removed
from.
Some
models
also
include
an
adaptor
plate
to
cover
unpainted
surfaces.
Thermostat
wires
pass
through
the
adaptor
plate
center
opening.
1.
Remove
Old
Thermostat:
A
standard
heat/cool
thermostat
consists
of
three
basic
parts:
a.
The
cover,
which
may
be
either
a
snap-on
or
hinge
type.
b.
The
base,
which
is
removed
by
loosening
all
captive
screws.
c.
The
switching
subbase,
which
is
removed
by
unscrewing
the
mountin
g
screws
that
hold
i
t
on
the
wall
or
adaptor
plate.
Make
a
note
here
I
I
of
the
anticipator
setting
on
the
old
thermostat
for
future
reference
and
use
in
step
5.
The
heat
anticipator
pointer,
if
adjustable,
will
be
set
at
one
of
a
series
of
numbers
representing
the
current
rating
of
the
primary
control
in
your
furnace.
The
number
will
be
one
of
the
following:
.2,
.4,
.8,
etc.
or
0.2,
0.4,
0.8,
etc.
If
no
heat
anticipator/indication
is
showing,
do
not
be
concerned;
move
on
to
the
next
step.
Printed
in
U.S.A.
PART
NO.
37-6377B
Replaces
37-6377A
0217
0
REMOVING
OLD
THERMOSTAT
CONTINUED
FROM
FIRST
PAGE
ATTENTION!
This
product
does
not
contain
mercury.
How¬
ever,
this
product
may
replace
a
unit
which
contains
mercury.
Do
not
open
mercury
cells.
If
a
cell
becomes
damaged,
do
not
touch
any
spilled
mercury.
Wearing
non-absorbent
gloves,
take
up
the
spilled
mercury
and
place
into
a
container
which
can
be
sealed.
If
a
cell
becomes
damaged,
the
unit
should
be
discarded.
Mercury
must
not
be
discarded
in
household
trash.
When
the
unit
this
product
is
replacing
is
to
be
discarded,
place
in
a
suitable
container
and
return
to
White-Rodgers
at
9797
Reavis
Road,
St.
Louis,
MO,
63123-5398
for
proper
disposal.
MOUNTING
AND
WIRING
A
WARNING
Do
not
use
on
circuits
exceeding
specified
voltage.
Higher
voltage
will
damage
control
and
could
cause
shock
or
fire
hazard.
Do
not
short
out
terminals
on
gas
valve
or
primary
control
to
test.
Short
or
incorrect
wiring
will
damage
thermostat
and
could
cause
personal
injury
and/or
property
damage.
Thermostat
installation
and
all
components
of
the
sys¬
tem
shall
conform
to
Class
II
circuits
per
the
NEC
code.
A
CAUTION
Take
care
when
securing
and
routing
wires
so
they
do
not
short
to
adjacent
terminals
or
rear
of
thermostat.
Personal
injury
and/or
property
damage
may
occur.
New
Thermostat
Terminal
Designation
Other
Manufacturers'
Terminal
Designation
RH
4
RH
M
R5
1
RC
R
R
V
-
G
G
G
F
G
(
W
W
W
H
4
\
Y
Y
Y
C
Y6
*
These
are
four-wire,
single-transformer
systems
Factory
installed
jumper
wire
between
the
RH
and
RC
terminals
must
remain
r\
place
D.
Mount
Thermostat
Base:
Gently
push
excess
wire
back
into
the
wall
opening
and
plug
hole
with
a
fire-resistant
material,
such
as
fiberglass
insulation
to
prevent
drafts
from
affecting
thermostat
operation.
Mount
the
thermostat
base
to
the
sub¬
base
using
the
three
captive
screws
on
the
thermostat
base.
(See
Fig.
1)
Tighten
the
screws
securely.
Remove
paper
tag
from
plastic
contact
cover.
Proceed
to
Step
#
5.
903990,
903994
&
918082
(Heat
Only
Two
Wire):
A.
Mount
base
and
adaptor
plate:
Mount
base
and
adaptor
plate
(optional)
to
wall
using
screws
provided
(see
Fig.
1).
B.
Attach
wires:
Attach
one
wire
to
R
and
the
other
wire
to
W
on
base.
C.
Skip
to
Step
#
5
.
903992
&
918081
(Heating
and
Cooling):
A.
Remove
base
from
subbase:
Loosen
the
three
screws
on
the
base
and
remove.
B.
Mount
switching
subbase/adaptor
plate:
Use
the
screws
provided
to
mount
the
subbase
and
adaptor
plate
(optional)
to
wall
(see
Fig.
1).
C.
Attach
wires
to
appropriate
terminals:
•
For
two
wire
systems
(Heat
Only
or
Cool
Only),
if
you
have
a
two-wire
Heat
Only
system,
attach
one
wire
to
RH
and
one
to
wire
W.
If
you
have
a
two-wire
Cool
Only
system,
attach
one
wire
to
RC
and
one
to
wire
to
Y.
Leave
the
factory
installed
jumper
between
RC
and
RH
attached.
Tighten
any
unused
terminals
securely.
•
If
your
system
has
more
than
two
wires:
Use
the
cross
reference
chart
to
determine
correct
wire
connections.
If
you
have
a
four-wire
heat/cool
system
leave
the
factory
installed
jumper
between
RC
and
RH
attached
(see
Fig
2.).
If
your
system
has
five
wires
remove
the
factory
installed
jumper
between
RC
and
RH
(see
Fig
3.).
Figure
2.
Typical
wiring
for
single
transformer
heating/cooling
system
Figure
3.
Typical
wiring
for
two-transformer
heating/cooling
system
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0
SET
HEAT
ANTICIPATOR
Set
anticipator
to
match
the
setting
of
your
old
thermostat
you
noted
in
Step
3,
or,
the
anticipator
should
be
set
to
match
the
current
rating
stamped
on
your
main
heating
control.
The
heat
anticipator
is
adjustable
from
0.15
to
1.2
amps.
Adjust
the
antici¬
pator
by
rotating
the
contact
arm
(see
fig.
5).
The
anticipator
setting
is
indicated
by
the
numbers
on
the
base
that
the
pointer
points
to.
If
you
are
unsure
where
to
set
the
anticipator
contact
the
heater
manufacturer
for
a
recommended
setting.
Move
the
pointer
counterclockwise
to
lengthen
heating
system
cycles;
move
clockwise
to
shorten
heating
cycles.
Adjustments
should
not
be
greater
than
1/2
marking
at
a
time.
Snap
on
Cover:
Carefully
align
the
cover
with
the
base
and
snap
the
cover
onto
the
base.
NOTE
Rotate
contact
arm
to
adjust
heat
anticipator
For
Miiivoit
Application:
Rotate
contact
arm
to
rest
on
this
rivet.
Arrow
points
to
the
current
rating
of
the
primary
coontrol
Figure
5.
Anticipator
adjustment
Typical
Gas
Valve
50/60
Hz
C
?3
Ampg
>
Typical
Oil
Primary
Typical
Zone
Valve
0
NEW
THERMOSTAT
OPERATION
903990,903994
&
918082
Heat
Only
-
After
power
is
turned
on,
slide
temperature
lever
to
desired
setting.
To
turn
heat
off,
slide
lever
all
the
way
to
the
left
until
it
clicks.
903992
&
918081
-
This
thermostat
is
easy
to
operate.
Fig.
6
shows
how
the
heating/cooling
system
and
fan
operate
when
the
switches
are
in
various
positions.
After
power
is
turned
on,
use
the
system
switch
to
select
either
heating
or
cooling,
or
to
turn
the
heating/cooling
system
off.
Use
the
fan
switch
to
control
fan
operation.
When
the
fan
switch
is
in
the
AUTO
position,
the
fan
will
cycle
with
the
heating
or
cooling
system
(the
fan
will
not
run
if
the
system
switch
is
in
the
OFF
position
and
the
fan
switch
is
in
the
AUTO
position).
When
the
fan
switch
is
in
the
ON
position,
the
fan
will
run
continuously,
regardless
of
system
switch
position
(even
if
the
system
switch
is
set
to
OFF,
the
fan
will
run
if
the
fan
switch
is
in
the
ON
position).
■
Shows
switch
position
OPERATION
FAN
□
□
AUTO
ON
COOL
OFF
HEAT
■
□
□
■
□
No
heating;
no
cooling;
no
fan
□
■
□
■
□
No
heating;
no
cooling;
tan
runs
continuously
□
■
Cooling
system
cycles
from
thermostat:
fan
runs
continuously
■
□
Cooling
system
and
tan
cycle
from
thermostat
■
□
Heating
system
cycles
from
thermostat;
fan
cycles
from
fan
control
on
furnace
□
■
Heating
system
cycles
from
thermostat;
fan
runs
continuously
Figure
6.
Subbase
switching
and
thermostat/system
operation
(903992
&
918081
only)
0
SPECIFICATIONS
ELECTRICAL
DATA
Switch
Rating
.
24
VAC
(30
VAC
max.)
Heating.0.15
to
1.2
Amps
Cooling.Oto
1.5
Amps
Switch
Action
.
Snap
Action
Anticipator
Rating:
Heating.Adjustable
from
0.15
to
1.2
Amps
Cooling.Fixed
THERMAL
DATA:
Temperature
Range
.
50°F
to
90°F
(10°C
to
32°C)
Operating
Humidity
Range
...0
-
90%
noncondensing
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)
TROUBLESHOOTING
Symptom
Possible
Cause
Corrective
Action
No
Heat/No
Cool/No
Fan
(common
problems)
1
.
Blown
fuse
or
tripped
circuit
breaker.
2.
Furnace
power
switch
to
OFF.
3.
Furnace
blower
compartment
door
or
panel
loose
or
not
properly
installed.
Replace
fuse
or
reset
breaker.
Turn
switch
to
ON.
Replace
door
panel
in
proper
position
to
engage
safety
interlock
or
door
switch.
No
Heat
1.
Pilot
light
not
lit.
2.
Broken
or
melted
anticipator
wire.
3.
Loose
connection
to
thermostat
or
system.
4.
Thermostat
or
heating
system
requires
replacement
or
service.
5.
System
Switch
not
set
to
Heat.
Re-light
pilot.
Excessive
current
or
dead
short
in
system.
Have
a
qualified
service
person
check
the
system
before
replacing
thermostat.
Verify
thermostat
and
system
wires
are
securely
attached.
Your
furnace
manufacturer
or
service
person
car
describe
how
to
test
the
heating
system
to
verify
it
is
operating
correctly.
If
the
heating
system
is
capable
of
operation
and
the
no
heat
condition
persists,
replace
the
thermostat.
Set
System
Switch
to
Heat
and
raise
temp
above
room
temp.
Intermittent
Heat
1.
Furnace
Lock-Out
Condition
Many
furnaces
have
safety
devices
that
shut
the
system
down
when
a
lock-out
condition
occurs.
If
the
heat
works
intermittently
contact
the
furnace
manufacturer
or
local
service
person
for
assistance
No
Cool
1.
Loose
connection
to
thermostat
or
system.
2.
Thermostat
or
cooling
system
requires
replacement
or
service.
3.
System
Switch
not
set
to
Cool.
Verify
thermostat
and
system
wires
are
securely
attached.
Your
cooling
system
manufacturer
or
service
person
can
describe
how
to
test
the
cooling
system
to
verify
it
is
operating
correctly.
If
the
cooling
system
is
capable
of
operation
and
the
r>
cooling
condition
persists,
replace
the
thermosta
Set
System
Switch
to
Cool
and
lower
temp
below
room
temp.
Heat,
Cool
or
Fan
Runs
Constantly.
1
.
Possible
short
in
wiring.
2.
Possible
short
in
thermostat.
3.
Possible
short
in
heat/cool/fan
system.
Check
each
wire
connection
to
the
thermostat
to
verify
it
is
neatly
looped
under
the
terminals.
No
extra
wire
should
stick
out
from
under
the
terminals.
Furnace
Cycles
Too
Fast
or
Too
Slow
Narrow
or
wide
temperature
swing
See
Step
5,
Adjusting
the
Anticipator.
The
anticipation
setting
is
the
only
adjustment
th
effects
the
heating
cycle
rate.
If
an
acceptable
cycle
rate
is
not
achieved
using
the
anticipator
contact
a
local
service
person
for
additional
suggestions.
The
location
of
the
thermostat,
size
of
the
Heat/Cool
System
and
current
draw
can
influence
the
cycle
rate.
Cooling
Cycles
Too
Fast
or
Too
Slow
(narrow
or
wide
temperature
swing)
1.
Poor
thermostat
location
for
sensing
room
temperature.
2.
Cooling
system
over
or
undersized.
3.
Excessive
Current
draw
influencing
thermostat.
The
cycle
rate
for
cooling
can
not
be
adjusted
The
location
of
the
thermostat,
size
of
the
Cool
system
and
current
draw
can
influence
the
cycle
rate.
Contact
a
local
service
person
for
suggestions.
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This manual suits for next models
4
